Statistical Dynamics of Flow-Driven Globular Polymers

Cherayil, BJ (2022) Statistical Dynamics of Flow-Driven Globular Polymers. In: Journal of Physical Chemistry B, 126 (27). pp. 5127-5136.

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Abstract

The response of collapsed polymers to the effects of linear mixed flow is studied theoretically in this paper using a model of a self-interacting finitely extensible Gaussian chain that evolves stochastically in the presence of random thermal fluctuations and an external fluid velocity gradient. The interactions that produce compact chain configurations are described by a harmonic pair potential of strength κ that acts between nonbonded sites on the chain backbone. Several chain properties are calculated analytically from this model as a function of κ for elongational and shear flows, including the dependence of the chain's steady-state mean-square end-to-end distance on the Weissenberg number of the flow, the time-dependence of the chain's relaxation to equilibrium from a steady-state of given chain extension, and the nature of the force-extension curves that are obtained from the free energy change between unperturbed and flow-stretched states of the chain. For both elongational and shear flows (but to different degrees), it is found that the greater the value of κ (and the more compact the chain), the more difficult it is, in general, for the imposed flow to induce a transition between compact and extended states, in broad agreement with available data from numerical simulations. For the relaxation process, the differences between the two flow types are more marked. The characteristic decay time for relaxation from a state prepared by elongational flow is essentially independent of κ, whereas in the case of a state prepared by shear flow, it is distinctly κ-dependent, the relaxation becoming faster at larger κ.

Item Type:	Journal Article
Publication:	Journal of Physical Chemistry B
Publisher:	American Chemical Society
Additional Information:	The copyright for this article belongs to the American Chemical Society.
Keywords:	Chains; Free energy, Chain configuration; Compact chains; Fluid velocities; Gaussian chains; Globular polymers; Mixed flows; Statistical dynamics; Steady state; Thermal fluctuations; Velocity gradients, Shear flow, polymer, normal distribution, Normal Distribution; Polymers
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	27 Sep 2022 07:34
Last Modified:	27 Sep 2022 07:34
URI:	https://eprints.iisc.ac.in/id/eprint/77206

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